分别使用3种方式创建学生对象，定义姓名、年龄、性别等属性，打招呼和跑的方法，使用for in 来遍历对象，将对象的属性和方法输出

当然可以。以下是三种创建学生对象的方式：

1. **传统JavaScript类**:

class Student {
  constructor(name, age, gender) {
    this.name = name;
    this.age = age;
    this.gender = gender;
  }
  
  sayHello() {
    return `你好，我是${this.name}，今年${this.age}岁。`;
  }

  run() {
    return `${this.name}正在跑步...`;
  }
}

// 创建3个实例
let student1 = new Student("小明", 18, "男");
let student2 = new Student("小红", 20, "女");
let student3 = new Student("小华", 19, "男");

// 使用for...in遍历并打印属性和方法
for (let attr in students = [student1, student2, student3]) {
  console.log(`${attr}:`, students[attr]);
  if (typeof students[attr] === 'function') {
    console.log(`${attr}() => ${students[attr].call(students[attr])}`);
  }
}

2. **ES6 JavaScript类（箭头函数）**:

const Student = ({name, age, gender}) => ({
  sayHello: () => `你好，我是${name}，今年${age}岁.`,
  run: () => `${name}正在跑步...`,
});

let student1 = Student({name: "小明", age: 18, gender: "男"});
let student2 = Student({name: "小红", age: 20, gender: "女"});
let student3 = Student({name: "小华", age: 19, gender: "男"});

// 遍历对象
for (let student of [student1, student2, student3]) {
  for (let key in student) {
    console.log(`${key}:`, student[key]);
    if (typeof student[key] === 'function') {
      console.log(`${key}() => ${student[key]()}`);
    }
  }
}

3. **使用JavaScript的对象字面量和原型链（模拟类）**:

function Student(name, age, gender) {
  this.name = name;
  this.age = age;
  this.gender = gender;
}

Student.prototype.sayHello = function() {
  return `你好，我是${this.name}，今年${this.age}岁。`;
};

Student.prototype.run = function() {
  return `${this.name}正在跑步...`;
};

// 创建3个实例
let student1 = new Student("小明", 18, "男");
let student2 = new Student("小红", 20, "女");
let student3 = new Student("小华", 19, "男");

// 遍历对象
for (let i = 0; i < 3; i++) {
  let student = students[i];
  for (let prop in student) {
    console.log(`${prop}:`, student[prop]);
    if (typeof student[prop] === 'function') {
      console.log(`${prop}() => ${student[prop].call(student)}`);
    }
  }
}